Dynamic Engine Oil Temperature Control via Variable Thermostat Threshold

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Solution Overview

Problem

Existing engine lubrication systems face challenges in reducing oil ageing and wear while maintaining effective friction reduction, particularly at high temperatures and heavy load conditions.

Innovation Solution

An engine assembly with a lubrication system that includes a control unit and sensors to dynamically adjust the lubricating oil temperature based on real-time operating conditions, using a heat exchanger and adjustable flow paths to optimize the temperature for reduced friction and minimized wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thermostat maintains lubricating oil temperature within a limited range by routing oil through the heat-exchanging path, then friction reduction is improved, but oil ageing and wear increase at high temperatures and heavy load conditions

Engineering Contradiction:
Improvefriction reductionVSAvoidoil ageing and wear
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the thermostat threshold temperature based on engine operating conditions (load, speed, temperature). At heavy load conditions, the threshold is raised to allow higher operating temperatures that reduce friction, while at light load conditions, the threshold is lowered to prevent oil ageing and wear. This dynamic adaptation resolves the contradiction by optimizing temperature based on real-time operational context.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the thermostat's threshold temperature parameter from a fixed value to a variable value that depends on engine operating conditions. The control unit modifies the threshold parameter based on sensors detecting load, speed, and temperature, allowing the system to shift between friction-reduction mode (higher temperature) and protection mode (lower temperature) to eliminate the trade-off.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the thermostat allows higher lubricating oil temperatures to minimize friction, then friction reduction is improved, but oil ageing and wear increase

Engineering Contradiction:
Improvefriction lossesVSAvoidengine wear and oil ageing
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system dynamically adjusts the thermostat threshold temperature based on engine operating conditions (load, speed, temperature). At heavy load conditions, the threshold is raised to allow higher operating temperatures that reduce friction, while at light load conditions, the threshold is lowered to prevent oil ageing and wear. This dynamic adaptation resolves the contradiction by optimizing temperature based on real-time operational context.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the thermostat's threshold temperature parameter from a fixed value to a variable value that depends on engine operating conditions. The control unit modifies the threshold parameter based on sensors detecting load, speed, and temperature, allowing the system to shift between friction-reduction mode (higher temperature) and protection mode (lower temperature) to eliminate the trade-off.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a fixed thermostat threshold is used to maintain lubricating oil temperature, then temperature control is simplified, but the system cannot adapt to varying engine load conditions

Engineering Contradiction:
Improvetemperature control systemVSAvoidadaptation to operating conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The thermostat system is enhanced with multi-functionality: it not only controls temperature based on a threshold but also receives inputs from multiple sensors (load sensor, speed sensor, temperature sensor) and adapts its behavior accordingly. The control unit integrates multiple functions - reading sensor data, determining operating conditions, adjusting threshold, and controlling the thermostat - making the system universally adaptable to various operating scenarios while maintaining reasonable complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements feedback control by continuously monitoring engine operating conditions through sensors and using this information to adjust the thermostat threshold temperature. The control unit receives feedback from load, speed, and temperature sensors, processes this information to determine current operating conditions, and dynamically adjusts the threshold to optimize performance for the specific operating context, enabling adaptation without excessive complexity.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for continuous and stable adjustment of lubricating oil temperature, reducing fuel consumption by minimizing friction at low loads and preventing excessive wear and oil ageing at high loads, achieving a balance between friction reduction and engine longevity.

Implementation Method 1

the oil circuit includes a heat-exchanging path, in which at least a partial quantity of the lubricating oil taken from the engine flows and transfers heat to a secondary cooling medium

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the thermostat starts admitting the oil flow to the heat-exchanging path when the temperature above overcomes a fixed threshold, which is peculiar of the thermostat

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3828394B1An engine assembly having an engine and a lubrication system for delivering lubricating oil to the engine
Publication Date: 2022.12.28 FPT MOTORENFORSCHUNG AG
  • EP3828394B1 patent drawingFigure 1
  • EP3828394B1 patent drawingFigure 2
  • EP3828394B1 patent drawingFigure 3

AI summary

An engine assembly (1) is provided with an engine (2) and with a lubrication system (3) for circulating oil from/to the engine (2) and including an oil circuit (12) and an oil conditioning apparatus (23, 21) for allowing temperature conditioning of the circulating oil, wherein the engine assembly further include a sensor assembly (28) for detecting values associated to operative parameters of the engine (2), as well as for generating a first signal associated to the detected values, and a control unit (ECU) that receives the first signal and extract a first amount of information therefrom relative to values of the operative parameters, wherein the oil conditioning apparatus (23) includes also an adjustment device (27) that is controllable to cause a temperature variation of a portion of the circulating oil, and wherein the control unit (ECU) controls the adjustment device (27) based on the extracted first amount of information.